WHAT IS SPUTUM (MYCOBACTERIA) TEST?
Mycobacteria are rod-shaped, aerobic bacteria that resist decolorizing chemicals after staining, hence “acid–fast.” Many new species of nontuberculous mycobacteria (or new components of species complexes), as well as multiple drug-resistant isolates of M. tuberculosis, have been recognized. Mycobacterium species are capable of producing human disease characterized by destructive granulomas that can necrose, ulcerate, and cavitate. M. tuberculosis is transmitted by the airborne route, most commonly to the lungs, where it survives well, causes areas of granulomatous inflammation, and, if not dormant, causes cough, fever, and hemoptysis. In this test, an acid-fast bacteria (AFB) culture and stain of sputum are performed to detect mycobacteria. The smear is followed by a confirmatory culture. Sputum culture for M. tuberculosis obtains a higher yield and is more cost-effective than blood culture. Newer methods of testing for tuberculosis include polymerase chain reaction and nucleic acid amplification (Palomino, 2006).